Original Publication Date: 2002-Jun-01
Included in the Prior Art Database: 2003-Jun-19
Disclosed is a function for Manufacturing Execution System (MES) for semiconductor manufacturing plants. Summary: This is to allow MES to transfer reticle from a reticle stocker to a exposer tool, such as wafer stepper or wafer scanner. Background: Exposer tool is to project circuit pattern on the reticle onto wafers by ultra violet rays or other light sources. Current MES systems are designed to maximize the utilization of exposer tools. Operators in the manufacturing plant loads reticles before exposer operation starts. MES system dispatch wafers to exposer tools that right reticle have already loaded. In this way, set-up time to change reticles in the exposer tools are minimized. This results the best productivity to the large scale production of standard products, typically for 200 mm wafers. When wafer size is changing from 200 mm to 300 mm, semiconductor manufacturers want to build custom products for profitable product portfolio. This requirement to MES is changing from exposer tool utilization to turn around time (TAT) of the custom product. To shorten the TAT, wafers should be processed as soon as they arrived at the exposure process. Functions: When a cassette or a FOUP arrives at the exposure process, MES requests transfer system of wafers to move them to the exposer tools as soon as one of the exposer tools becomes ready to load next wafers. When the exposure process starts, the right reticle for the process should be loaded in the exposer tool. To do this, MES system will control the reticle reservation state. The reticle reservation state is reserved, unreserved and in-use. When a cassette or a FOUP is dispatched to the exposer tool, MES changes the selected reticle status to unreserved to reserved, or keep it in-use. In this way MES can request reticle transfer system to move the reticle to the right exposer tool when the wafers are dispatched. The reticle arrives to the exposer tool on time. This control of the reticle reservation state prevents the reticle to be removed away from the reticle before the exposure operation completed. If the reticle is loaded in another exposer tool, MES may request the reticle transfer system from the exposer tool that loads the reticle to the right exposer tool.